Arrangement for irradiating an object with radioactive radiation



Sept. 13, 1966 A. KOHN ETAL 3,272,987

ARRNGEMENT FOR IRRADIATING AN OBJECT WITH RADIOACTIVE RADIATION Sept.13, 1966 A. Kol-1N ETAL 3,272,987

ARRANGEMENT FOR IHRADIATING AN OBJECT WITH RADIOACTIVE RADIATION Sept.13, 1966 A. KoHN ETAL 3,272,987

ARRANGEMENT FOR IRRADIATING AN OBJECT WITH RADIOACTIVE RADATION FiledOct. 24, 1962 4 Sheets-Sheet 5 Sept. 13, 1966 A. KoHN ETAL T FORIRRADIATING AN OBJECT 3,272,987 ARRANGEMEN WITH RADIOACTIVE RADIATION 4Sheets-Sheet 4 Filed 001'.. 24, 1962 /nyao/o/'S Hadre'. H050 /ean Huf CUnited States Patent O 3,272,937 ARRANGEMENT FR IRRADIATING AN OBJECTWITH RADIOACTHVE RADIATIN Andr Kohn, Saint-Germain-en-Laye, and .leanAupe, lLe Pecq, France, assign-ors to Institut de Recherches de laSiderurgia Francaise, Saint-Germain-en-Laye, France Filed (let. 24,1962, Ser. No. 232,827 (Ilaims priority, application France, Nov. 7,1961, 878,165, Patent 1,313,153 13 Claims. (Cl. Z50- 106) The presentinvention concerns an arrangement for irradiating an object withradioactive radiation, a method becoming more and more popular invarious industries eg. in rolling mills for examining sheet material inthe course of its manufacture so as to detect flaws, to determine itsthickness or the like.

However, it is well known that such radioactive radiation e.g. gammaradiation constitutes a considerable hazard for the personnel.Therefore, a body of radioactive material intended to be used forirradiating an object is ordinarily shielded by being enclosed in aheavy container composed predominantly of material absorbing radioactiveradiation. Of course, the container must have at least one openingthrough which the desired radioactove radiation can be released indirection toward the object to be irradiated. For the sake of safetyagainst unintentional irradiation of objects or personnel this openingwould have to be normally covered and be uncovered only when irradiationof an object is desired. A cover establishing safety would have to bevery heavy and as thick as the lwalls of the protective container, andtherefore it would require considerable forces to move the cover betweena position in which the opening of the container is covered and aposition in which it is uncovered. In addition, alone on account of theconsiderable inertia of such a heavy cover its movement between theabove mentioned positions could hardly be carried out with the highspeed which is desirable.

Particularly in th'e case of the application of an arrangement forirradiating an object With radioactive radiation in a steel or othermetal rolling mill, rapid or even instantaneous changes betweenirradiating condition and protected condition of the irradiatingarrangement is of great importance.

It is therefore one of the objects of this invention to provide for anarrangement for irradiating an object with radioactive radiation whichprovides for the above mentioned changes to take place with greatrapidity and by applications of a comparatively moderate force.

It is another object of this invention to provide for an arrangement ass'et forth which is comparatively simple in its structure and entirelyreliable in operation.

With above objects in view the invention includes an arrangement forirradiating an object with radioactive radiation, comprising, incombination, container means composed predominantly of materialabsorbing .radioactive radiation and including an inner chamber ofpredetermined dimensions, said container means further including achannel leading in a predetermined direction from a selected portion ofsaid inner chamber to the outside of said container means; a body of4radioactive material arranged Within said inner chamber and havingdimensions smaller than those of said inner chamber so as to be movabletherein between a first position in which said body of radioactivematerial is located opposite the inner end of said channel whereby itsradiation is released to the outside in said direction of said channeltoward an object that may be present opposite the outer end of saidchannel, and a second position in Which said body of radioactivemateria-l is located within said inner chamber at a distance from saidinner end of said 3,272,987 Patented Sept. 13, 1966 channel whereby saidradiation is blocked from reaching the outside; and moving meansalternatively moving said body of radioactive material from said firstposition t-o said second position, and vice versa.

The novel features which are considered as characteristic for th'einvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specilicembodiments when read in -connection with the accompanying drawings, inwhich:

FIG. 1 is a schematic diagram illustrating one e-mbodiment of theinvention with a body of radioactive material in shielded position;

FIG. 2 is a similar illustration of the same embodiment showing the bodyof radioactive material in op- 'erative position for irradiating anobject;

FIG. 3 is a -schematic diagram illustrating a simplified embodiment ofthe invention, with the body of radioactive material in shieldedposition; and

FIG. 4 illustrates the same arrangement as FIG. 3, with the body ofradioactive material in operative position for irradiating an object.

In the embodiment illustrated by FIGS. 1 and 2 a thick-wall container 3made predominantly of material absorbing radioactive radiation isprovided with an inner chamber 3 of predetermined dimension, thelefthand portion whereof is connected by a channel 4 in a predetermineddirection transverse of the longitudinal dimension of the chamber 3 withthe outside surface of the container 3. A carrier 2 supporting a body 1of radioactive material is arranged for being movable in longitudinaldirection along the chamber 3 between a first position in which the body1 of radioactive material is located opposite the inner end of thechannel 4, as shown in FIG. 2, whereby radiation from the body 1 isreleased in the above mentioned direction through the channel 4 to theoutside, and a second position, shown in FIG. 1, spaced a certaindistance from the inner end of the channel l whereby radiation from thebody 1 through the channel 4 is prevented. For controlling the movementof the carrier 2 with the body 1 a second channel 3" extends inlongitudinal direction of the chamber 3 through the entire block orcontainer 3 so that guide rods 7 and 7 may be moved slidably along thissecond channel 3".

For moving the carrier 2 with its body 1 of radioactive material ahydraulic or pneumatic device is provided which comprises a cylinder Sand a piston 6 movable therein and connected with the guide rod 7. Thetwo opposite ends of the cylinder 5 are connected by Huid lines 8 and9', respectively, with solenoid valves 8 and 9, respectively. Bothvalves are constructed in the same manner. For instance, the valve 8comprises a body and a control plunger 12 with transverse bores so that,depending upon the position of the plunger 12, the uid line 8 is eitherconnected with a pressure fluid input line 10 coming from a source ofcompressed iiuid medium (gas or liquid) or with an exhaust line S". Inthe same manner the control plunger 13 of valve 9 connects dependingupon its position either the uid line 9 with the supply line 10 or withan exhaust line 9". Solenoid means 11 and 11a, respectively, cooperatewith the plungers 12 and 13, respectively, so as to move the latter,upon energization of the solenoid, from a first position as shown inFIG. 1 for the valve 9, to a second position as shown in FIG. 1 forvalve t8, Spring means or the like may be provided for returning theplungers from said second position to said first position as indicatedby the arrows 12' and 13', respectively.

When the valves 8 and 9 are in the positions as illustrated in FIG. 1i.e. when the solenoid 11 is energized, the pressure fluid from supplyline is applied through valve 8 and line 8 to one side of the piston 6so that the latter is moved in the direction of the arrow 6 whereby thecarrier 2 with the radioactive body 1 is placed in the position shown inFIG. l in which radiation from the body 1 to the outside is blocked.While the piston 6 has been moved in the direction of arrow 6 thepressure fluid on the other side thereof has been permitted to escapethrough line 9' and through valve 9 and the exhaust line 9".

However, when the valves 8 and 9 are in the position shown in FIG. 2 thepressure fluid from line 10 is applied through valve 9 and line -9 tothe other side of the piston 6 so that it is moved in the direction ofarrow 6 whereby the carrier 2 with the body 1 is moved to its positionin which the radiation from the body 1 is released through channel 4.During the movement of the piston 6 in the direction of the arrow 6" thepressure uid on the first side of the piston 6 has been permitted toescape through line y8 and valve 8 to the exhaust line 8l. K

The solenoids 11 and 11a are connected, as shown, with a controlledsource of electric energy B. This source may comprise for instancerelays which depending upon their energization apply electric currentalternatively either to the solenoid 11 or to the solenoid 11a. Thesource B or the above mentioned relays therein may be controlled bymanual control C for intentionally establishing either the position ofthe valves as shown in FIG. l or the position of the valves asillustrated by FIG. 2.

It will be understood that, although the use of hydraulic means asdescribed above in connection with solenoid valves is preferred, themovement of the carrier 2 between its positions may quite as well becarried out by other conventional means as for instance byelectromagnetic actuation of the guide rod 7 or 7.

It should be borne in mind that solenoid valves are available whichoperate with -great rapidity so that by using such solenoid valves greatrapidity of the movement of the carrier 2 with its body of radioactivematerial 1 can be accomplished.

It will be understood that by the arrangement described above safetyagainst unintentional release of radiation through the channel 4 can beachieved additionally by arranging in the cylinder 5 a spring or similardevice as illustrated at 6a in FIGS. 3 and 4, which continuously exertsforce on the piston 6 in the direction of the arrow 6'. In this casewhenever either the electric power or the supply of pressure fluidshould fail the piston 6 will by all means be moved to the positionshown in FIG. 1 in which radiation from the body 1 to the outside isblocked.

The above described arrangement lends itself readily to automaticcontrol and operation. For this purpose photoresponsive ydevices may bearranged opposite the outer end of the channel 4 and connected with thecontrolled source B through an automatic control device A so thatdepending upon energization and de-energization of the photo-responsivemeans the controlled source B is correspondingly -controlled or actuatedin a manner analogous to the above described manual control.

In a preferred embodiment as illustrated by FIGS. 1 and 2 twophoto-cells 14a and 14b are arranged opposite the channel 4 but spacedfrom each other a predetermined distance so that the midpoint betweenthe cells 14a and 14b is substantially in alignment with the center lineof channel 4. The photo-cells 14a and 14b are so connected with theautomatic control A and the latter is so constructed that the controlledsource B is actuated in one or the other way only when both photo-cells14a yand 14b are simultaneously energized or one of them isde-energized, as the case may be.

The reason for this and for the use of two photo-cells in thisarrangement is the following. The purpose of the automaticphoto-electric control is to automatically move the carrier 2 with theibody 1 into radiation-releasing position according to FIG. 2 only whenan object 15 as shown in FIG. 2 moving in the direction of the arrow Xhas reached a position in which it intercepts the entire beam 4 ofradioactive radiation released through channel 4. Since this beamcomposed e.g. of gamma rays, has a 4certain tendency to diverge asillustrated, and since the object 15, for instance a sheet or strip ofmetal to be irradiated, may reach the position of being irradiated notonly in the direction of the arrow X but also in opposite direction,using only one photo-cell located on the center line of channel 4 mightresult in the release of radioactive radiation from the channel 4 beforethe radioactive beam 4 is fully intercepted by the front end of theobject 15.

If the object 15 is hot so as to release infra-red radiation 15 as shownin FIG. 2 then of course the photocells 14a and 14b should be sensitiveto infra-red radiation. When energized by such radiation they will causethe automatic control A to actuate the controlled source B in such amanner that the valves 8 and 9 are placed in the condition shown in FIG.2 and correspondingly the body 1 of radioactive material is placedopposite the inner end of the channel 4. On the other hand, whenever theobject 15 is not in a position to intercept the radioactive beam 4', atleast one of the photo-cells 14a or 14b is de-energized whereby in amanner analogous to that described above the carrier 2 with the body 1is automatically removed to the position according to FIG. l.

Ilf the material of the object 15 does not emit infra-red radiation butis simply lopaque then a slightly different arrangement should be used.As `indicated in FIG. l one or two light sources 14C, 14e should beplaced in the area of the outer end of the channel 4 so as to throwlight beams 14 and 14", respectively, in direction toward thephoto-cells 14a and 14b. Thus both photo-cells 14a and 14b are normallyenergized simultaneously. If now an opaque object 15 is moved into aposition in which it intercepts not only the radioactive beam 4' butalso the light beams 14 and 14" the photo-cells 14a and 14b aresimultaneously de-energized. In this case this simultaneousde-energization of the photo-cells 14a and 14b will cause the automaticcontrol A to actuate the controlled source B so as to cause movement ofthe carrier 2 with the body 1 into the position of FIG. 2. On the otherhand, as soon as .the object 15 is withdrawn so that at least one of thephoto-cells 14a or 14b is again energized by one or the other of thelight sources 14C or 14e the automatic control A Will cause in analogousmanner as described above the automatic movement ot the carrier 2 withthe body 1 to the position illustrated by FIG. 1.

FIGS. 3 and 4 correspond in general to the arrangement illustrated byFIGS. 1 and 2 except that the arrangement is somewhat simplified.Instead of two valves only one valve 9 is provided which serves in theposition shown by FIG. 4 to cause application olf Ithe pressure fluidthrough line 9' to the cylinder 5 so as to move the piston 6 in thedirection of arrow 6 whereby the carrier 2 with the body 1 is placed inposition opposite the channel 4. A return spring 6a is provided in thecylinder 5 for returning Ithe piston 6 and with it the carrier 2 to theposition as shown in FIG. 3. This return movement will take place assoon as the solenoid valve 9 is de-energized and assumes t-he positionshown in FIG. 1. The operation of this simplified arrangement isotherwise quite analogous to that described above with reference toFIGS. 1 and 2.

It can be seen that also `the arrangement according to FIGS. 3 and 4offers added safety in the case of failure of the electric power or ofthe supply of pressure fluid because the spring 6a tends always toreturn the carrier 2 with the body 1 into the blocked position.

Evidently the arrangement could be advantageously supplemented by one ormore relays or similar means which respond to other general conditionsapplying to the area where the irradiation arrangement according to theinvention is located so that by this relay or these relays either theelectric supply to the control arrangement or the supply of pressurefluid, or both, are interrupted, or that by actuation of the controlledsource B the arrangement is actuated to move t-he body l into blockedposition, whenever lthe general conditions mentioned above are suc-hthat the release of radiation from the body 1 must be or should beprevented.

Practical tests with an arrangement according to the invention haveshown that it operates in a very sensitive and rapid manner. Themovement `oi the carrier 2 with the radioactive body i betweenradiation-releasing position and blocked position takes place withinabout .l second after energization olf the photo-cells 14a and llb andthis is achieved by applying air pressure of 85 p.s.i. to the piston 6.

`It will be understood that each orf the elements described above, ortwo or more together, may also find a useful application in other typesof an arrange-ment tor irradiating an object with radioactive radiationdiffering from the types described above.

While the invention has been illustrated and described as embodied in anarrangement for irradiating an object with radioactive radiation bymeans of automatic movement of a radioactive body between aradiation-releasing position and a radiation-blocking position, it isnot intended to be l-imited to the details shown, since variousmodiiications and structural changes may be made without departing inany way from the spirit orf the present invention.

Without rfurt-her analysis, the foregoing will so lfully reveal the gistIof the present invention that others can by applying current knowledgereadily adapt it for various applications without omitting teaturesthat, yfrom the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specic aspects of this invention and,therefore, such adaptations should and Vare intended to be comprehendedwithin the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured -by Letters Patent is:

ll. An arrangement for irradiating lan object with radioactiveradiation, comprising, in combination, container means composedpredominantly of material absorbing radioactive radiation and includingan inner chamber of predetermined dimensions, said container meansfurther including a channel leading 4in a predetermined direction from aselected portion of said inner chamber to the outside of said containermeans; la body of radioactive lmaterial arranged within .said innerchamber and having dimensions smaller than those of said inner chamberso as to be movable therein between a first position in which said bodyof radioactive material is located opposite the inner end of saidchannel whereby its radiation is released to the outside in saiddirection of said channel toward an object that may be present oppositethe outer end of said channel, anda second position in which said bodyof radioactive material -is located within said inner chamber at adistance from said inner end of said channel whereby said radiation isblocked from reaching the outside; moving means for alternatively movingsaid body of radioactive material from said first position to saidsecond position, and vice versa; and control means in operativeproximity with said body of radioactive material and in the area of saidobject and electrically connected to said moving means for controllingthe 'operation of said moving means in accordance with the position ofsaid object relative to said radiation.

2. An arrangement for irradiating an object with radioactive radiation,comprising, in combination, container means composed predominantly ofmaterial absorbing radioactive radiation and including an inner chamberof predetermined dimensions, said container means further including afirst channel leading in a predetermined direction from a selectedportion of said inner chamber to the outside of said container means anda second channel leading from said inner chamber in at least onedirection transverse of said predetermined direction of said firstchannel to the outside of said container means; carrier means movablewithin said inner chamber and in said second channel; :a body ofradioactive material arranged Within said inner chamber and havingdimensions smaller than those of said inner chamber and supported bysaid carrier means, said carrier means with said body lof radioactivematerial being movable between a iirst position in which said body ofradioactive material is located opposite the inner end of said channelwhereby its radiation is released to the outside in said direction ofsaid channel toward an object that may be present opposite the outer end`of said channel, and a second position in which said body ofradioactive material is located within said inner chamber at a distancefrom said inner end of said channel whereby said radiation is blockedfrom reaching the outside; moving means for alternatively moving saidcarrier means with said body of radioactive material from said rirstposition to said second position, and vice Versa; and control means inoperative proximity with said body of radioactive material and in the4area of said object and electrically connected to said moving means forcontrolling the operation of said moving means in accordance with theposition of said object relative to said radiation.

3. An arrangement for irradiating an object with radioactive radiation,comprising, in combination, container means composed predominantly ofmaterial absorbing radioactive radiation 4and including an inner chamberof predetermined dimensions, said container means further including aiirst channel leading in a predetermined direction from a selectedportion of said inner chamber to the outside of said container means anda second channel leading from said inner chamber in at least onedirection transverse of said predetermined direction of said iirstchannel to the outside of said container means; carrier means movablewithin said inner chamber and in said second channel; a body ofradioactive material arranged within said inner chamber and havingdimensions smaller than those of said inner chamber and supported bysaid carrier means, said carrier means with said body of radioactivematerial being movable between a first position in which said body ofradioactive material is located opposite the inner end of said channelwhereby its radiation is released to the outside in said direction ofsaid channel toward 1an object that may be present opposite of saidfluid medium to said hydraulic means; and control means in operativeproximity with said body of radioactive material and in the area of saidobject and electrically connected to said moving means for controllingthe operation of said lmoving means in accordance with the position ofsaid iobject relative to said radiation; said body of radioactivematerial is located within said inner chamber at a distance from saidinner end of said channel whereby said radiation is blocked fromreaching the outside; moving means for alternatively moving said carriermeans with said body of radioactive material from said first position tosaid second position, and vice versa, said moving means includinghydraulic means responsive t-o the application thereto of a fluid mediumunder pressure and iluid control means for controlling the applicationof said fluid medium to said hydraulic means and control means inoperative proximity with said body of radioactive material and in thearea of said object and electrically connected to said moving means forcontrolling the operation of said moving means in accordance with theposition of said object relative lto said radiation, said control meansbeing responsive to said radiation.

4. An arrangement as defined in claim 3 wherein said hydraulic meanscomprises cylinder and piston means, and

wherein said fiuid medium causes movement of said piston means inresponse to control by said fluid control means.

5. An arrangement as defined in claim 3 wherein said hydraulic meanscomprises double-acting cylinder and piston means, and wherein saidfiuid medium causes alternatively movement of said piston means in oneand the opposite direction, respectively in response to control by saidfluid control means.

6. An arrangement as defined in claim 2 wherein said moving meansincludes cylinder and piston means causing movement of said piston andcarrier means to said first position in response to the applicationthereto of a fiuid medium under pressure, resilient means for causingreturn movement -of said piston and carrier means when pressureapplication is dis-continued and fiuid control means for controlling theapplication of said fiuid medium to said cylinder means for causingmovement of said piston means toward said first position.

7. An arrangement as defined in claim 6 wherein said uid control meansincludes a source of compressed fiuid medium and fiuid line means tosaid cylinder means, and further comprising solenoid valve means-arranged in said fluid line means and changeable between opened andclosed condition depending upon electrical energization, and electricmeans for energizing said solenoid valves.

8. An arrangement as defined in claim 7 wherein said cylinder and pistonmeans are double-acting cylinder and piston means, wherein said fluidcontrol means causes alternative movement of said piston means in oneand the opposite direction, respectively, and said iiuid line meansincludes first and second fluid line means to the opposite ends,respectively, of said cylinder means, said solenoid valve means beingarranged in said first and second fluid line means, respectively andeach being changeable between opened and closed condition, and furthercomprising electric means for alternatively energizing one of saidsolenoid valve means to assume open condition while causing the otherone to assume closed condition, and vice versa.

9. An arrangement as claimed in claim 7, wherein said control meansinclude infra-red light responsive means located substantially oppositethe outer end of said first channel in said predetermined directionthereof for causing energization of said solenoid valve means when anobject to be irradiated and emitting itself infra-red light radiation isplaced between said outer end of said first channel and said infra-redlight responsive means.

-10. An arrangement as claimed in claim 8, wherein said control meansinclude infra-red light responsive means located substantially oppositethe outer end of said first channel in said predetermined directionthereof for causing, when an object to be irradiated and emitting itselfinfra-red light radiation is placed between said outer end of said firstchannel and said infra-red light responsive means energization of saidfirst solenoid valve means, for causing opening of the latter andcorrespondingly movement of said carrier means to said first positionthereof.

11. An arrangement as claimed in claim 8, wherein said control meansinclude light source means located in the area of the outer end of saidfirst channel and light responsive means located substantially oppositethe outer end of said first channel in said predetermined directionthereof for causing, when an opaque object to be irradiated is placedbetween said outer end of said first channel and said light responsivemeans, energization of said first solenoid valve means for causingopening of the latter and correspondingly movement of said carrier meansto said first position thereof.

12. An arrangement as claimed in claim S, wherein said control meansinclude infra-red light responsive means located substantially oppositethe outer end of said first channel in said predetermined directionthereof for causing, when an object to be irradiated and emitting itselfinfra-red light radiation is placed between said outer end of said firstchannel and said infra-red light responsive means, energization of saidsolenoid valve means for causing opening of the latter andcorrespondingly movement of said carrier means to said first positionthereof.

13. An arrangement as claimed in claim 5, wherein said control meansinclude light source means located in the area of the outer end of saidfirst channel and light responsive means located substantially oppositethe outer end of said first channel in said predetermined directionthereof for causing, when an opaque object to be irradiated is placedbetween said outer end of said first channel and said light responsivemeans, energization of said solenoid valve means for causing opening ofthe latter and correspondingly movement of said carrier means to saidfirst position thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,732,083 1/1956Smith 214-658 2,822,776 2/1958 Morganstern 250-106 2,965,761 12/1960Harvath 250-106 2,999,591 9/1961 Crump 250-83.3 3,032,661 5/1962 WolfZ50-106 RALPH G. NILSON, Primary Examiner.

JAMES W. LAWRENCE, Examiner.

S. ELBAUM, Assistant Examiner.

1. AN ARRANGEMENT FOR IRRADIATING AN OBJECT WITH RADIOACTIVE RADIATION,COMPRISING, IN COMBINATION, CONTAINER MEANS COMPOSED PREDOMINANTLY OFMATERIAL ABSORBING RADIOACTIVE RADIATION AND INCLUDING AN INNER CHAMBEROF PREDETERMINED DIMENSIONS, SAID CONTAINER MEANS FURTHER INCLUDING ACHANNEL LEADING IN A PREDETERMINED DIRECTION FROM A SELECTED PORTION OFSAID INNER CHAMBER TO THE OUTSIDE OF SAID CONTAINER MEANS; A BODY OFRADIOACTIVE MATERIAL ARRANGED WITHIN SAID INNER CHAMBER AND HAVINGDIMENSIONS SMALLER THAN THOSE OF SAID INNER CHAMBER SO AS TO BE MOVABLETHEREIN BETWEEN A FIRST POSITION IN WHICH SAID BODY OF RADIOACTIVEMATERIAL IS LOCATED OPPOSITE THE INNER END OF SAID CHANNEL WHEREBY ITSRADIATION IS RELEASED TO THE OUTSIDE IN SAID DIRECTION OF SAID CHANNELTOWARD AN OBJECT THAT MAY BE PRESENT OPPOSITE THE OUTER END OF SAIDCHANNEL, AND A SECOND POSITION IN WHICH SAID BODY OF RADIOACTIVEMATERIAL IS LOCATED WITHIN SAID INNER CHAMBER AT A DISTANCE FROM SAIDINNER END OF SAID CHANNEL WHEREBY SAID RADIATION IS BLOCKED FROMREACHING THE OUTSIDE; MOVING MEANS FOR ALTERNATIVELY MOVING SAID BODY OFRADIOACTIVE MATERIAL FROM SAID FIRST POSITION TO SAID SECOND POSITION,AND VICE VERSA; AND CONTROL MEANS IN OPERATIVE PROXIMITY WITH SAID BODYOF RADIOACTIVE MATERIAL AND IN THE AREA OF SAID OBJECT AND ELECTRICALLYCONNECTED TO SAID MOVING MEANS FOR CONTROLLING THE OPERATION OF SAIDMOVING MEANS IN ACCORDANCE WITH THE POSITION OF SAID OBJECT RELATIVE TOSAID RADIATION.